Sakurai/pdf.js
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reasonably fast for black and white images

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sbarman 2011-06-27 10:38:10 -07:00
parent 2fdb200626
commit c4d50b7677
1 changed files with 53 additions and 44 deletions
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97
pdf.js
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@ -4444,80 +4444,87 @@ var PDFImage = (function() {
};
constructor.prototype = {
getCompFunction: function getCompFunction(bpc, width, numComps, buffer) {
getComponents: function getComponents(buffer) {
var bpc = this.bpc;
if (bpc == 8)
return buffer;
var width = this.width;
var height = this.height;
var numComps = this.numComps;
var length = width * height;
var bufferPos = 0;
var output = new Uint8Array(length);
if (bpc == 1) {
var rowComps = width * numComps;
var curComp = 0;
var mask = 0;
var buf = 0;
var getComp = function() {
if (mask <= 0) {
buf = buffer[bufferPos++];
mask = 128;
}
var ret = buf & mask;
curComp++;
if (curComp % rowComps == 0) {
for (var i = 0, ii = length; i < ii; ++i) {
if (i % rowComps == 0) {
mask = 0;
buf = 0;
} else {
mask >>= 1;
}
return ret * 255;
}
} else if (bpc == 8) {
var getComp = function() {
return buffer[bufferPos++];
if (mask <= 0) {
buf = buffer[bufferPos++];
mask = 128;
}
var t = buf & mask;
if (t == 0)
output[i] = 0;
else
output[i] = 255;
}
} else {
var rowComps = width * numComps;
var curComp = 0;
var bits = 0;
var buf = 0;
var getComp = function() {
for (var i = 0, ii = length; i < ii; ++i) {
while (bits < bpc) {
buf = (buf << 8) | buffer[bufferPos++];
bits += 8;
}
var remainingBits = bits - bpc;
var ret = buf >> remainingBits;
curComp++;
if (curComp % rowComps == 0) {
if (i % rowComps == 0) {
buf = 0;
bits = 0;
} else {
buf = buf & ((1 << remainingBits) - 1);
bits = remainingBits;
}
return Math.round(255 * ret / ((1 << bpc) - 1));
output[i] = Math.round(255 * ret / ((1 << bpc) - 1));
}
}
return getComp;
return output;
},
getOpacityFunction: function getOpacityFunction() {
getOpacity: function getOpacity() {
var smask = this.smask;
var width = this.width;
var height = this.height;
var buf = new Uint8Array(width * height);
if (smask) {
var w = smask.width;
var h = smask.height;
if (w != this.width || h != this.height)
var sw = smask.width;
var sh = smask.height;
if (sw != this.width || sh != this.height)
error("smask dimensions do not match image dimensions");
var buf = new Uint8Array(w * h);
smask.fillGrayBuffer(buf);
var bufPos = 0;
var opacity = function() {
return buf[bufPos++];
}
return buf;
} else {
var opacity = function() { return 255; }
for (var i = 0, ii = width * height; i < ii; ++i)
buf[i] = 255;
}
return opacity;
return buf;
},
fillRgbaBuffer: function fillRgbaBuffer(buffer) {
var numComps = this.numComps;
@ -4530,26 +4537,28 @@ var PDFImage = (function() {
var imgArray = this.image.getBytes(height * rowBytes);
var imgPos = 0;
var getComp = this.getCompFunction(bpc, width, numComps, imgArray)
var getOpacity = this.getOpacityFunction();
var comps = this.getComponents(imgArray);
var compsPos = 0;
var opacity = this.getOpacity();
var opacityPos = 0;
var length = width * height * 4;
switch (numComps) {
case 1:
for (var i = 0; i < length; i += 4) {
var p = getComp();
var p = comps[compsPos++];
buffer[i] = p;
buffer[i+1] = p;
buffer[i+2] = p;
buffer[i+3] = getOpacity();
buffer[i+3] = opacity[opacityPos++];
}
break;
case 3:
for (var i = 0; i < length; i += 4) {
buffer[i] = getComp();
buffer[i+1] = getComp();
buffer[i+2] = getComp();
buffer[i+3] = getOpacity();
buffer[i] = comps[compsPos++];
buffer[i+1] = comps[compsPos++];
buffer[i+2] = comps[compsPos++];
buffer[i+3] = opacity[opacityPos++];
}
break;
default:
@ -4569,11 +4578,11 @@ var PDFImage = (function() {
var rowBytes = (width * numComps * bpc + 7) >> 3;
var imgArray = this.image.getBytes(height * rowBytes);
var getComp = this.getCompFunction(bpc, width, numComps, imgArray)
var comps = this.getComponents(imgArray);
var length = width * height;
for (var i = 0; i < length; ++i)
buffer[i] = getComp();
buffer[i] = comps[i];
},
};
return constructor;